“Healthy obesity” is a misnomer, according to new research from University College London (UCL). A study published in the Journal of the American College of Cardiology finds that good health isn’t sustainable in the long term for most obese people. The study shows that obesity generally worsens health even in otherwise healthy individuals. It also shows that obesity contributes to a host of complications over time.

“Healthy obesity is only healthy in a relative sense — in that the risk of disease is lower than for unhealthy obese adults, but still higher than for healthy normal-weight adults,” said lead study author Joshua Bell, a Ph.D. student in the department of epidemiology and public health at UCL. “And as we now see, healthy obese adults tend to become unhealthy obese in the long term, providing further evidence against the idea that obesity can be healthy.”

Obesity in the Long Term

The concept of healthy obesity has been hotly debated within the medical community. The term refers to a state of obesity with no metabolic comorbidities. These comorbidities include type 2 diabetes.

It was the longest running study of its kind. Researchers surveyed more than 2,500 volunteers over a 20-year period. They wanted to determine whether healthy obese adults maintained their metabolic health long-term or if they transitioned into unhealthy obesity.

More than 180 of the participants were initially classified as obese. Sixty-six of them were classified as healthy obese. More than 51 percent of previously healthy obese participants were deemed unhealthy obese at the 20-year mark. Just 6 percent of people in the healthy obese group lost weight and became healthy non-obese at the end of the first five years.

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Does Healthy Obesity Really Exist?

A handful of studies in the past few years have suggested that metabolically healthy obesity does not pose as serious a risk of long-term health problems as other factors.

The American College of Cardiology challenged these claims in a study asserting that healthy obese people still have an increased risk of heart disease. Their increased risk is due to a higher rate of early plaque buildup in their arteries.

Heart disease is just one of many health linked to obesity.

“The idea of healthy obesity may have persisted for several years due to inconsistent early evidence on disease risks, and to a lack of awareness of its instability in the long-term,” Bell said. “We know that healthy obese adults have a greater risk for type 2 diabetes and cardiovascular disease than healthy normal-weight adults, and, as we can now see, healthy obesity itself is often just a phase.”

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Calling obesity healthy at all can be harmful “if it reduces the perceived need to prevent or seek treatment for obesity,” said Christopher Ochner, Ph.D., a nutrition and obesity expert at The Mount Sinai Hospital in New York City. Ochner was not involved in the study.

“We want to fight the false stigma that individuals with obesity lack willpower, but that is not accomplished by creating the false notion that obesity is not associated with significant medical comorbidities,” Ochner added. “More effort needs to be put into helping people understand that obesity is a medical disease, like diabetes.”

Working Toward Lifelong Health

While obese individuals can and do strive to lead healthy lives, the condition itself makes achieving health-related goals all the more challenging.

“When being physically active, an obese adult’s health may improve in the short-term even if weight is not lost, due to reductions in harmful types of fat, increases in muscle, and reduced inflammation, and this is certainly a positive step,” Bell said. “However, our results stress the need to take a long-term view of healthy obesity, as there is a tendency for healthy obese adults to progress to ill-health over time. Healthy obesity is still a high-risk state — the harmful effects may just be delayed.”

Discussing solutions to obesity can be a sensitive topic. Promoting a positive and realistic body image is also essential to the conversation. Studies such as this one highlight the importance of maintaining a healthy weight for a lifetime.

“We encourage individuals with obesity to seek help for weight loss in order to improve their health, quality of life, and life expectancy, not in an attempt to meet the media’s unrealistic portrayals of beauty,” Ochner said. “These are, in fact, damaging and we want people to realize that a healthy body contains both muscle and fat, and different shapes and sizes are beautiful, but obesity should be avoided.”